- A
Increase the SQS batch window size
Why wrong: Batch window affects polling frequency, not CPU performance.
- B
Switch the Lambda runtime from Python to Node.js
Why wrong: Runtime change may not significantly help CPU-bound processing.
- C
Increase the Lambda function's memory allocation
More memory provides more CPU, speeding up CPU-bound tasks.
- D
Enable Provisioned Concurrency for the function
Why wrong: Provisioned Concurrency reduces cold starts, not execution time.
Question 275 of 1,616
How to Reduce Execution Time for CPU-Bound Lambda Functions
This DVA-C02 practice question tests your understanding of development with aws services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer is building a serverless application using AWS Lambda to process events from an Amazon SQS queue. The Lambda function is CPU-bound and currently experiences timeouts. What is the MOST cost-effective way to reduce execution time?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the Lambda function's memory allocation
Increasing the Lambda function's memory allocation is the most cost-effective way to reduce execution time for a CPU-bound function because Lambda allocates CPU proportionally to memory. More memory means more vCPU capacity, which directly speeds up CPU-bound processing. This reduces the function's duration, and since Lambda billing is based on compute time (GB-seconds), the total cost can decrease even if the per-GB-second rate is higher.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the SQS batch window size
Why it's wrong here
Batch window affects polling frequency, not CPU performance.
- ✗
Switch the Lambda runtime from Python to Node.js
Why it's wrong here
Runtime change may not significantly help CPU-bound processing.
- ✓
Increase the Lambda function's memory allocation
Why this is correct
More memory provides more CPU, speeding up CPU-bound tasks.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Enable Provisioned Concurrency for the function
Why it's wrong here
Provisioned Concurrency reduces cold starts, not execution time.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume increasing memory only helps memory-bound workloads, but AWS Lambda's CPU allocation scales with memory, making it the primary lever for CPU-bound performance improvements.
Detailed technical explanation
How to think about this question
Lambda allocates CPU power linearly in proportion to the configured memory, up to a maximum of 6 vCPUs at 10,240 MB. For CPU-bound workloads, doubling memory can nearly halve execution time, often reducing total cost because the duration decrease outweighs the higher per-GB-second rate. This is due to the underlying hypervisor's CPU credit mechanism, which ties compute capacity directly to memory allocation.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
What to study next
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FAQ
Questions learners often ask
What does this DVA-C02 question test?
Development with AWS Services — This question tests Development with AWS Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the Lambda function's memory allocation — Increasing the Lambda function's memory allocation is the most cost-effective way to reduce execution time for a CPU-bound function because Lambda allocates CPU proportionally to memory. More memory means more vCPU capacity, which directly speeds up CPU-bound processing. This reduces the function's duration, and since Lambda billing is based on compute time (GB-seconds), the total cost can decrease even if the per-GB-second rate is higher.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This DVA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DVA-C02 exam.
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